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Integrated master capstone · Lesson 2 of 4

Integrated master capstone: materials, standards and design constraints

Wind and edge securement, thermal movement, fabrication limits and metal compatibility: which document supplies each number, whose value it is, and what to do when two documents disagree.

You will be able to: Identify the four constraint families on edge metal, name which document or register supplies each, and recognise when two documents conflict.

13 min · 12 slides · 10 questions

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Slide 1 of 12

Four constraints, four sources

Four families of constraint govern edge metal, and a different document answers each.

  • Wind and edge securement: ES-1 test results and the engineer of record
  • Thermal movement: the metal's coefficient, the run length and the metal temperature
  • Fabrication limits: AFS's limits register
  • Metal compatibility: the specification and the maker's guide
The four constraints on edge metal at a glanceFour tiles. Wind and edge securement: ES-1 tests RE-2 and RE-3, and the engineer applies the factor. Thermal movement: dL = alpha x L x dT with metal temperature; 40, 32 and 12 ft joint intervals in one federal specification. Fabrication limits: flat width 48 inches at most, piece 126 inches at most, 10 ft standard, from the AFS register. Metal compatibility: aluminum contact rules and isolation from treated lumber. A footer: 59 percent of built-up roof losses in one 2005 FM Global study occurred because the roof perimeter failed, as quoted by SPRI.Four constraints on one sheetWind and edge securementES-1 tests RE-2 (face pull)and RE-3 (top and face together)The engineer applies the factorStandards body, makerThermal movementdL = alpha x L x dTUse metal temperature40 / 32 / 12 ft joints in one federal specAgency specFabrication limitsFlat width 48 in at mostPiece 126 in at most10 ft is the standard pieceAFS registerMetal compatibilityAluminum: no direct contactwith most other metalsIsolate metal from ACQ lumberSpec and maker59% of built-up roof losses in one 2005 FMGlobal study occurred because the roofperimeter failed, as quoted by SPRI.AFSStandard, agencySpec, maker

Four tiles: wind and edge securement with ES-1 tests RE-2 and RE-3; thermal movement with dL = alpha x L x dT and 40, 32 and 12 ft joint intervals in one federal specification; fabrication limits of 48 in flat width, 126 in piece and a 10 ft standard; metal compatibility. A footer gives 59 percent of built-up roof losses in one 2005 FM Global study.

Tile colour shows the source type: AFS register in red, standards body and agency specification in blue, specification and maker in teal.

Sources

Glossary

ES-1
ANSI/SPRI/FM 4435/ES-1, the test standard for low-slope perimeter edge metal, excluding gutters, with test methods RE-1, RE-2 and RE-3.
RE-2
The ES-1 test of outward pull on the vertical face of an edge device, run on a full-size specimen cycled until failure.
RE-3
The ES-1 test for coping caps: face and top loads applied together at 1.73 vertical to 1.00 horizontal.
Sustained pressure
The pressure Drexel prints for a tested coping system, in psf, negative for outward. The Design Engineer must apply the factor of safety.
Free movement
The change in length of an unrestrained run, dL = alpha x L x dT, using the metal surface temperature.
Expansion joint interval
The largest distance a specification allows between expansion and contraction joints; UFGS 07 60 00 gives 32 ft for aluminum and 40 ft for other metals.
Galvanic action
The corrosion UFGS 07 60 00 guards against where dissimilar metals touch, and a topic SPRI lists as galvanic compatibility in ED-1.
Nailer
The member an edge system is fastened to. SPRI says ES-1 does not test nailers and ED-1 gives guidance on nailer attachment.